The present invention relates to data switching systems and is more particularly concerned with the scheduling and arbitration arrangements for such systems.
The continual growth of demand for manageable bandwidth in networks requires the development of new techniques in switch design which decouples the complexity of control from the scale of the port count and aggregate bandwidth. This invention describes a switch architecture and a set of methods which provide the means by which switches of arbitrary size may be constructed whilst maintaining the ability to allocate guaranteed bandwidth to each possible connection through the switch. A digital switch is used to route data streams from a set of source components to a set of destination components. A cell-based switch operates on data which is packetized into streams of equal size cells. In a large switch the routing functions may be implemented hierarchically, that is sets of lower bandwidth ports are aggregated into a smaller number of higher bandwidth ports which are then interconnected in a central switch.
It is an object of the present invention to provide a bandwidth allocation arrangement which may be used in such a hierarchical switch.